Can you solve the prisoner hat riddle? - Alex Gendler

You and nine other individuals have been captured by super-intelligent alien overlords. The aliens think humans look quite tasty, but their civilization forbids eating highly logical and cooperative beings. Unfortunately, they’re not sure whether you qualify, so they decide to give you all a test. Can you solve this hat riddle? Alex Gendler shows how.

Lesson by Alex Gendler, animation by Artrake Studio.

[dkssudgktpady]

only one serious problem of this riddle : everyone must understand your plan

[ishaangupta]

Unfortunately when you pick 10 humans at random there's gonna be a lot of idiots

[TurkishKS]

Even if one person in the group could figure this out, imagine trying to explain this strategy to 9 other average humans in 5 minutes.

[gabereese]

Realistically, the aliens would've also said that they aren't allowed to touch their hats, or otherwise remove them from theirs or each others' heads, to prevent them from just looking at their hats or switching them around.

[anikabhardwaj]

Imagine everything is going as planned and the last person calculates his colour wrong and everyone dies

[bub]

blind person: *exists*
the nine other prisoners: yeah we're screwed

[hithereireallysuck]

3:25 Was this whole thing just a setup to call me short? Because you're absolutely correct, and I applaud you for calling me out in such a subtle, yet clever fashion!

[j-ymoney]

“Quick, What do we do?!”

“No idea…”

[rudrasatwik]

"Now it all comes down to you, in the front of the line."
*Curses genetics for making him short*

[chenjiafan]

Me an intellectual: *takes off my hat and looks because it’s not against the rules*

[StarsShatteredBeyond]

“But their civilisation forbids eating highly logical and cooperative beings” That does not describe humanity at all 💀

[Opposition]

We did this in special ed class a while ago, and it was quite a traumatizing experience, as my classmates didnt explain it to me and I kept failing everytime, so I went crying in the corner

[canadianrage]

Imagine actually coming up with this genius plan and spending the next 5 minutes carefully explaining it to everyone, just for the last person to screw up and cost everyone their lives.

[anonymousanonymous]

Alternate strategy: Take off your hat and look. It's still allowed via the rules given

[florianhovelmann]

This can be extended to any amount of colors. Let's say we have three colors red, green and blue. First we assign a value to each red=0, green=1, blue=2. The person starting to guess a color adds up the color values of each hat he sees and takes it modulo 3. For example for a lineup of (r, g, g, r, b, g) the sum would be 1+1+0+2+1=5%3=2, so he says blue. The next one does a similar calculation 1+0+2+1=4%3=1 and subtracts this from what the last person has said, leading to 2-1=1=green and so on.

Interestingly, the riddle gets simpler if you use an infinite amount of colors. Again assigning values to them, and for simplicity just consider the values instead of colors. The person starting simply adds up all the values and says the corresponding color. Now the next person does the same and subtracts the result from what the last person said. So for a lineup of (12, 2, 43, 29, 1), the first one says 2+43+29+1=75, the second 75-(43+29+1)=2 and so on.

[TheBigGuyBillyBob]

Adisson Anderson is legitimately one of my favorite people on earth. His voice is the one all of my positive thoughts are set in.

[turtleshell]

honestly, if this plan was explained to me without any visuals within 5 minutes, i wouldn't even understand it 💀

[PaintToSample]

"It all comes down to you"


Me: wHiTe

[lucy-rdre]

my comp-sci teacher used to give us this problem when we started the logic module. it takes surprisingly long for a group of 12 year olds to figure out a solution for this.

[ChanwooPark-mewc]

이런 수수께끼들은 항상 다양한 관점에서 생각해 보아야 풀리는 것 같습니다. 정말 생각지도 못한 해답이었네요. 가끔씩 이런 문제들을 풀면 지루한 일상에서 벗어나는 기분이 듭니다. 앞으로도 이런 영상 많이 기대하겠습니다!